1. Field of the Invention
The present invention relates to an apparatus for manufacturing a semiconductor chip package, and more particularly to an in-line die attaching and curing apparatus for a multi-chip package.
2. Description of the Related Art
With the development of semiconductor technology, and the pressing demand of users, recent trends in the electronics industry are towards minimization, light-weight construction and multi-function. To meet these demands, multi-chip packaging techniques have been introduced. Multi-chip packages (MCPs) include a plurality of semiconductor chips of the same or different type in a single package. MCPs manufactured by such techniques are more advantageous in size, weight and mounting area than one including a plurality of packaged semiconductor chips. MCPs have been employed in semiconductor business uses requiring minimization and light weight characteristics, such as in portable computers and portable telephones.
The MCPs generally use a leadframe or substrate such as a chip mounting frame. The substrate may include a printed circuit board and a circuit film.
FIG. 1 is a cross-sectional view of an example of a conventional MCP. Referring to FIG. 1, the MCP 10 has a substrate 21, a first chip 11 attached onto the substrate 21, and a second chip 13 attached onto the first chip 11. Adhesives 27 and 28 are formed between the substrate 21 and the first chip 11, and between the first chip 11 and the second chip 13, respectively. The first and second chips 11 and 13 have respective electrode pads 12 and 14 on active surfaces thereof. The first and second chips 11 and 13 are attached such that the active surfaces of the first and second chips 11 and 13 face in an upward direction. Bonding wires 17 and 18 electrically connect the respective first and second chips 11 and 13 to the substrate 21. The first and second chips 11 and 13 and bonding wires 17 and 18 are sealed within an encapsulating structure 31 in order to protect them from the external environment. The encapsulating structure 31 is made of epoxy molding compound (EMC). Solder balls 35 are attached to the bottom surface of the substrate 21 to provide an external electrical connection. Gold stud bumps 15 are joined onto the electrode pads 14, and substrate bonding pads 22 are joined onto the substrate 21.
The MCP may be generally manufactured by employing wafer sawing, die attaching and wire-bonding processes, and then by molding and ball attaching processes. The wafer sawing process may divide a wafer into individual semiconductor chips. The die attaching process may attach the individual semiconductor chips onto a substrate or onto a lower chip. The wire-bonding process may electrically connect the semiconductor chips to the substrate. The above three processes may be utilized in more than one instance during the MCP manufacturing process. The molding process may encapsulate the semiconductor chips and bonding wires with an encapsulating structure. The ball attaching process may attach an external electrical connection terminal to the substrate.
In the manufacture of the MCP, a thin wafer is required for a thin package. A dicing tape may be required to prevent damage of the chip which may occur due to the fragility of the thin wafer. Adhesive means attaching the chip onto the substrate or onto the lower chip may include an adhesive tape or epoxy resin to improve the reliability of the package. The adhesive means used should be cured by a curing process. The die attaching and curing processes should repeat once for each chip.
Before initiating a die attaching process, a wafer fabrication process creates integrated circuits on a wafer surface. A tape mounting process may attach a dicing tape, such as a UV tape, to the backside of the wafer. A wafer sawing process may divide the wafer into individual chips.
FIG. 2 is a flow diagram useful for explaining a die attaching process of a conventional MCP manufacturing process. Referring to FIG. 2, the UV tape attached to the backside of the wafer is irradiated with UV light rays in order to easily separate the chips from the UV tape (S1). An adhesive is applied to a chip mounting area of a substrate. A first chip is then attached to the chip mounting area of the substrate with the adhesive (S2). The substrate including the first chip is heated at a predetermined temperature to improve the adhesion strength of the adhesive (S3). The adhesive is then applied to an active surface of the first chip, and a second chip is attached to the first chip with the adhesive (S4). The substrate having the second chip is also heated at a predetermined temperature (S5).
Conventionally, a UV radiation apparatus, a die attaching apparatus and a curing apparatus are installed independently. The overall process proceeds discontinuously because the operation of each apparatus or each step of the process is individually conducted in an independent manner and performs for a predetermined amount of work as a single unit. Such an overall process may require substantial time for transferring materials between the individual apparatuses, as well as significant production downtime between each process. Furthermore, many materials must be cured at low temperature over a long time period. Therefore, it will take a great deal of time to perform the curing process when these materials are used. Accordingly, for the reasons set forth above, the aforementioned conventional die attaching processes have the disadvantage of requiring considerable increased time for completing their implementation.